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一.用SqlConnection连接SQL Server
1..加入命名空间
using System.Data.SqlClient;
2.连接数据库
SqlConnection myConnection = new SqlConnection(); myConnection.ConnectionString = "user id=sa;password=sinofindb;initial catalog=test;data source=127.0.0.1;Connect Timeout=30"; myConnection.Open();
改进(更通用)的方法:
string MySqlConnection="user id=sa;password=sinofindb;Database =test;data source=127.0.0.1;Connect Timeout=30"; SqlConnection myConnection = new SqlConnection(MySqlConnection); myConnection.Open();
二。用OleDbConnection连接
1.加入命名空间
using System.Data.OleDb;
2.连接sql server
string MySqlConnection="Provider=SQLOLEDB;Data Source=localhost;Initial Catalog=test;Integrated Security=SSPI;";
SqlConnection myConnection = new SqlConnection(MySqlConnection); myConnection.Open();
3.连接Access(可通过建立.udl文件获得字符串)
string MySqlConnection="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\db2000.mdb;
Persist Security Info=False;
4.连接Oracle(也可通过OracleConnection连接)
string MySqlConnection="Provider=MSDAORA;Data Source=db; user id=sa;password=sinofindb";
三.创建Command对象
1.SqlCommand 构造函数
①初始化 SqlCommand 类的新实例。public SqlCommand();
SqlCommand myCommand = new SqlCommand();
②初始化具有查询文本的 SqlCommand 类的新实例。public SqlCommand(string);
String mySelectQuery = "SELECT * FROM mindata"; SqlCommand myCommand = new SqlCommand(mySelectQuery); ③初始化具有查询文本和 SqlConnection 的SqlCommand类实例。
Public SqlCommand(string, SqlConnection);
String mySelectQuery = "SELECT * FROM mindata"; string myConnectString = "user id=sa;password=;database=test;server=mySQLServer"; SqlConnection myConnection = new SqlConnection(myConnectString); SqlCommand myCommand = new SqlCommand(mySelectQuery,myConnection);
④初始化具有查询文本、SqlConnection 和 Transaction 的 SqlCommand 类实例。
public SqlCommand(string, SqlConnection, SqlTransaction);
SqlTransaction myTrans = myConnection.BeginTransaction(); String mySelectQuery = "SELECT * FROM mindata"; string myConnectString = "user id=sa;password=;database=test;server=mySQLServer"; SqlConnection myConnection = new SqlConnection(myConnectString); SqlCommand myCommand = new SqlCommand(mySelectQuery,myConnection, myTrans);
2.建立SqlCommand与SqlConnection的关联。
myCommand.Connection = myConnection;
或者:SqlCommand myCommand = myConnection.CreateCommand;
3.设置SqlCommand的查询文本。
myCommand.CommandText = "SELECT * FROM mindata";
或者第2种构造:SqlCommand myCommand = new SqlCommand(mySelectQuery);
给SqlCommand对象提供两个查询字符串,每个查询字符串访问不同的表,返回不同的结果集。
两个查询语句用分号分隔。
4. 执行命令。
ExecuteReader
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